In order to improve bonding of dental restorations to a tooth surface, particularly dentin, conditioners have been used to prepare the dentin surface for bonding with the restoration. Herein, a dentin conditioning system is one or more dentin conditioners. Dentin conditioning systems have been developed which comprise more than one conditioner. Until now, each has been applied separately. Bonding is fairly easy and routinely achieved on the enamel portion of tooth surfaces, however, the chemical makeup of dentin makes the process of bonding to dentin far more complicated. Dentin conditioning systems which use more than one conditioner improve bonding to dentin through the sequential application of two or more chemical compounds prior to application of an adhesive.
Several conditioning systems which use two or more chemical compounds have been determined to greatly improve the bonding strength of the restoration adhesive to the dentin. However, due to the incompatibility of the different chemical compounds, it has been thought that they must be kept separate and applied separately to the dentin. Additionally, some dentin conditioners become activated or oxidized upon exposure to oxygen. Thus, it is necessary to inhibit the exposure of oxygen to these compounds until the time of use. While the oxidation and/or activation of these compounds usually does not occur immediately upon exposure to oxygen, they are unable to maintain a shelf life in the presence of oxygen which extends much more than a typical business day of a dentist.
Some dentin conditioning systems provide one or more conditioners separately as powders which need be mixed with a solvent. However, since these chemicals in solution are unstable to oxygen exposure, the measuring and mixing must be done by the dentist at chairside just prior to application.
In order to inhibit the exposure of oxygen to a dentin conditioner, methods of packaging the conditioner in a substantially air-tight cartridge have been developed. These cartridges are used in complicated applicator guns and syringes of the types shown in FIG. 1. Loading and unloading of the cartridges within these guns and syringes present a cumbersome task. Also, complicated cartridges are required containing movable rubber stoppers and piercible rubber diaphragms which do not completely inhibit exposure of the cartridge contents to oxygen. An example cartridge is also shown in FIG. 1. The cartridge comprises a glass container 100 in which a single dentin conditioner liquid 101 is disposed. The cartridge has a metal collar 102 at one end which contains a rubber diaphragm 103. At an opposite end of the cartridge is a movable rubber stopper 104 which is moved toward the rubber diaphragm when in use. This forces the conditioner through a hollow needle (not shown) inserted through the diaphragm.
The guns and cartridges are also not completely cost effective. In addition to the complex nature of this applicator system, at least one or more subsequent applications of dentin conditioners are still required in order to complete the conditioning process, a time consuming and sometimes troublesome chore.
The John O. Butler Company of Chicago, Ill. has proposed the use of a crushable glass ampule for the application of a dentin desensitizer, which acts much differently than a dentin conditioner as defined herein. This is a chemical that is applied to exposed dentin to nullify cervical erosion / exposed root surface dentin hypersensitivity thus minimizing pain for up to six months. A single glass ampule is provided in a tube with a swab applicator at one end. The ampule is crushed to allow the tube contents to soak into the cotton swab at the end which is then brushed against the dentin to coat it with the desensitizer.
The present inventor knows of no prior dentin conditioning systems which enable simultaneous application of the conditioners of the system. Instead, the prior systems use sequential application of dentin conditioners when more than one conditioner is used.